Complicating Bour’s eventual return is the timing of his injury and recovery. The minor league regular season ends on or around Labor Day. Instructional league action won’t begin until later in September. That could leave Bour in a tough spot as far as getting the necessarily rehabilitation at-bats needed to regain his timing after a long layoff.

“You just don’t know how effective a guy is going to be after missing six weeks and then not really [getting] at-bats to get timing back,” Mattingly said. “You don’t know how effective they can be. To find out, you just kind of throw them in the lineup, and if they’re not effective, then it ends up hurting you actually more than it helps you.”

Bour’s injury, his third disabled-list stint in 13 months, brought to a halt what was looking like a breakout year. He hit .289 with a .366 OBP and .548 slugging percentage — all career-highs — along with 21 homers and 63 RBI.

Left-hander Wei-Yin Chen, sidelined for going on four months with left elbow issues, will begin a rehab assignment Thursday with the GCL Marlins.

That will be a step up in intensity from the simulated games he has been throwing. Chen had another Monday, two innings.

The Marlins anticipate Chen returning to the majors this year.

Odds & ends

The Marlins activated left-handed reliever Jarlin Garcia from the 10-day disabled list Tuesday. He spent the minimum amount of time sidelined with what the team called a left biceps strain. …

To make room for Garcia on the active roster, the Marlins designated righty reliever Javy Guerra for assignment. Guerra allowed four runs in 5 2/3 innings across four games for Miami. …

The Marlins also called up right-hander Severino Gonzalez, who has an active a seven-inning scoreless streak in the minors (split between Double-A Jacksonville and Triple-A New Orleans), to be their 26th man for the doubleheader Tuesday. Coincidentally, Gonzalez’s first day in the majors with the Marlins came against his only previous club, the Phillies.